Upload
others
View
5
Download
0
Embed Size (px)
Citation preview
Literature Seminar
Low Valent Ruthenium CatalyzedBond-Forming Reactions with Olefins
Shinya Handa (D1)
0 Introduction
Contents
1/9
0 Introduction ···································1 Dimerization of 2.5-norbornadiene
1.1 History ·····································1.2 Discovory ································1.3 Formation of Divalent Ruthenacyles ··········
3 Codimerization ········································· 7
Other examples (See below)· Dr. Suto's lit. seminar (2004.10.27); Direct substitution propargyl alcohol· Morimoto-kun's seminar (2007.11.21); Synergy of transition metal complex with acid/base catalyst
2 Ruthenium aqua complex ························ 5
4 Outlook & Remark ···································· 9
1
22
4
2007.11.28
M
C
C
C
CM
σ donation π back donation
Excellent reviews of Ru-Catalyzed reactions.Trost, B. M. et al. Angew. Chem., Int. Ed. 2005, 44, 6630.Mitsudo, T.-A. et al. Synlett 2001, 309. Murahashi, S.-I. et al. Chem. Rev. 1998, 98, 2599.
Ru
3.1 History3.2 Ru Catalyzed reaction
The name derives from Ruthenia, the Latin word for Rus', a historical area which includes present-day Ukraine, Belarus, and parts of Russia, Slovakia, and Poland. Karl Klaus named the element in honour of his birthland, as he was born in Tartu, Estonia, which was at the time a part of the Russian Empire.
(from wikipedia in English)
2/9
1.2 Discovery
1 Dimerization of 2.5-norbornadiene
PCTD: pentacyclo[6.6.0.02,6.03,13.010,14]tetradeca-4-11-dieneHCTD: heptacyclo[6.6.0.02,6.03,13.04,14.05,9.010,14]tetradecane
PCTDHCTD
Me2N
O
MeO2CCO2Me
Mitsudo, T.-A. and Watababe, Y. et al. J. C. S. Chem. Commun. 1994, 435.Mitsudo, T.-A. et al. J. Am. Chem. Soc. 1999, 121, 1839.
bicyclo[2,2,1]heptaneskeletone cannot be seen.What the mechanism ??
c.f. dimerized product of nbd
inductiontime
or
MeO2CCO2Me
CO2MeMeO2CMe2N
O
DMMl DMAc 4
3rd order dependency on nbd1st order dependency on catalyst
B A + dmfm
A + dmml
A + dmfm
A + dmml induction period generation of B
· time course study
1.1 History
+
2
O
[Ir(cod)2Cl]2
Metal-catalyzed [2+2] cycloaddition
Iridium: Osborn, J. A. et al. J. Am. Chem. Soc. 1973, 95, 598.
+ COca. 35% y.
Nickel: Noyori, R. et al. J. Am. Chem. Soc. 1973, 95, 1674.
48% y.
Ni(cod)2Ph3P
Ruthenium: Mitsudo, T.-A. et al. J. C. S. Chem. Commun. 1976, 722.
+
E
E
E
ERuH2(PPh3)4 up to 57% y.
A
DMFm
3/9
What 's the mechanism ??
but
There is no evidence 3a is the precursor.At least 2 C-C bond must be cleaved.
Proposed mechanism
required several steps
c.f.) Ibers, J. A.et al J. Am. Chem. Soc. 1981, 103, 3014.
MeO2C CO2Me
60 °C, tol
Ru(cod)(cot)
A BRu(cot)(dmfm)2
yellowmacrocrystal
MeO2CCO2Me
· Complexation with dimethyl maleate gave same crystal
bond lengthax: longereq: shorter
2%38% 45%
+ others5%
118
7
711
6
12
tetravalent5
4
Ru
4/9
1.3 Formation of Divalent Ruthenacycles Ura, Y. Mitsudo, T,-A. et al. Organometallics 2006, 25, 2934.
R
R
bicyclodecaneligand complexη2
η4
η4
η6
η4
η4 ruthenacycle
1-2:5-6-η4
1-4-η4
Ambiguity of the hapticity contributed togiving unoccupied orbital
Mitsudo, T,-A. et al. Organometallics 2000, 19, 5733.
further treatmentwith bidentate pligand did not
gave isolable complex
X-lay structure of 5
(dmfm)Ru
H E
OOMe
RuO
E
OMeO
E
MeO
H
RuP
P
OO
E
OMe
EMeO 5
PP P
Psp2 C-H
activation insertion
Proposed mechanism
Why does interesting dimerization occur??· sp2 C-H bond is activated due to the strain of the C-C double and also creavage of C-C single bond occurred.
· Electron deficient olefin played key role to acceralate the reaction.
strain
· Coordinative solvent THF made interaction with Ru center. In place of P ligand, sp2 C-H activation was prompted.
Personal Speculation
· Ru-carbonyl oxygene interaction is essential?Ru
OOMe
H
E
Ru was directed to b-H and via 5 membered ring coordination, sp2 C-H activation was promoted
carbonyl directioneasy formation of Ru-H species
5/9
2 Ruthenium Aqua Complex Mitsudo, T,-A. et al. Organometallics 2002, 21, 4960.Mitsudo, T,-A. et al. Organometallics 2005, 24, 5724.
H2O
RuInterestingly, dmfm ligand coordinated with Ru to same enantioface .(re,re)&(re,re) or (si,si)&(si,si)
(re) (si) (re,re) (re,re)
c.f.) Sustman. J. et al. J. Organomet. Chem. 1994, 470, 191.
(re,re) (re,re) (si,si) (si,si)
O7
O1
H2O coordinated with Ru center.Hydrogen bond with dmfm ligand.
4
meso chiral
4a 4b
4b
4a
7 was isolated in the case of dppm.7-dppm was intact with H2O and extra P ligand.
see page 4
Characters of Ru aqua complex 41HNMR
H2O δ 4.68
Shoulderappeared.
sharper
experimental calculated
rather broad&
split
geminal two protons of H2O are nonequivalent
(1) At –40 °C, peak corresponding to H2O became sharp temporary.(2) Under -70 °C two different peaks of H2O appeared. (split)
At higher temperature, H2O is equivalent.That is because...
(1) rotation or (2) exchange with outer H2O
η6η4
pale yellow powder
Scheme 1. Possible positional exchange process of the water protons via rotation and inversion
µ3-oxotetraruthenium clusterKondo, T. and Mitsudo, T.-A. et al J Organomet. Chem. 2007, 692, 530.
6/9
rotate
longer
longer
interaction
wider
lose 2 hydrogen bondsgain 2 hydrogen bonds
30.8 kcal/mol
18 kcal/mol
dissociative associative
Exchange of outer H2O
DFT calculations
H2O
H2O
H2O
H2O
Rotation of H2O isenergetically favorable.
What is the shoulder peak at –40 °C.
O
E
MeO
HO
Ru
OMe
E
O
HO
Ru
flip
Metal aqua complex as an asymmetric catalyst(物思いにふけってみました)
(1) chiral center is close to the substratesEffectively enantio-induction occurs?!
substratecoordination
site
chirality
(2) different kinds of interactions of substratesWider ranges of substarates are applicable.
chirality hydrogen bonding
metal coordination
(1) Examples of (S)-QUINAP complex
(S)-QUINAPClCH2CH2Cl
60 °C
29% y.
N
PPh3
(S)-QUINAPchiralitytransfer
(2) multifuctional complex
OO LaO
O
OO Li
Li
Li
· LiOH
2nd generation LLB
Low yield should be solved.Application to other metals
combinations ofLewis AcidBrønsted Acid X Lewis Base
Brønsted Base
chirality induction
O
H
HO
Ru
PP
EH
*N
C
*
image
8.5 kcal/molunstable
7/9
3 Codimerization of Olefins
Alderson, T.; Jenner, E. L.; Lindsey, R. V. Jr. J. Am. Chem. Soc. 1965, 87, 5638.
3.1 History
Gooßen, L. J. Angew. Chem., Int. Ed. 2002, 41, 3775.RajanBabu, T. V. Chem. Rev. 2003, 103, 2845.Gooßen, L. J. et al. Angew. Chem., Int. Ed. 2007, 46, 7544.
Reviews
H2C CH2
400 atm
RhCl3·H2O CH3
H3CH3C
CH3+ +
78% 20% 2%
Nickel-hydride catalyzed reaction
η3-intermediate
3.2 Low Valent Ru Catalyzed ReactionMitsudo, T.-A. et al. J. Org. Chem. 2005, 70, 6623.
[Ni]-H
dissociation of arene was difficult
NN N
tpy=
catalyst 3 wasutilized.
RuIII catalyst itself had no activity.
Ru0 is the active species.Alcohol is not necessary for dimerization.
proposed mechanisms
ruthenacyclopentane
β-elim.
red. elim.
c.f.) Brookhart, M. at al. J. Am. Chem. Soc. 1997, 119, 906 and references therein.
And also regioselectivity from the view of kinetic and thermodynamic controles, see Handa's lit. Seminar 060715 Pd catalyzed oxidative reactions
zerovalent
8/9
Kondo, T. et al. Angew. Chem., Int. Ed. 2007, 46, 5958.
induction period
CO2R[Ru]H
sp2 C-H activation
insertion
red. elim.
Path C
Also other mechanism can be thought. (Path C: one candidate)
β-H elimination from 7 cannot be explained predominat formation of trans-isomer.How did active catalys [Ru]-H generated ??
Path B
Path CAfter the C-H activation cis-isomermight be more stable? COR
[Ru] O
H
· no reaction occurred with divalent Ru complex.· linear adduct formed with (E) C=C double bond.· Primary alcohol is essential (3 equiv.).
(parehthasis is isolated yield)
What is the role of alcohol ?· Primary alcohol is essential (1-propanol, 1-octanol and ehanol)
Secondary, tertiary alcohol is not suitable.Alcohol interacted with Ru complex.
Time course study
almost no [D2]-2a or [D3]-2a
Generation of [Ru]-H which rapidly reacted with styreneand the product was intact to the active species.
insertion
red. elim.
active species
insertion
β elim.
ruthenacyclopentane
[Ru]
should bepredominant
[Ru]
acceleration of reactionor
direct other pathway
D distribution cannot be explained
alocohol played nothing.
Authers suggested path C. However, the observed phenomina is imcompatible.
9/9
3 Outlook & Remark
Ura, Y., Kondo, T. et al. Angew. Chem., Int. Ed. 2007, 46, 5160.
Is path B the most reasonable mechanism??
rapid equilibrium
thermodynamic
[Ru]
kinetic
[Ru]
c.f.) Stahl, S. S. et al. J. Am Chem Soc. 2005, 127, 17888.
· induction period ······· O· D distribution ······ ?· regioselectivies ······· O
[Ru]-H was generated Ru and alcohol.
Further mechanistic study is required.
cata
lytic
act
ivity
reaction condition
A A'B B'
Ru
Pd
Ru-catalyzed reactions
Reactivities, substrate scopes
························
········
································
cond
ition
A
condition B
[6+2] cycloadditionconsumed the substrate some extent.